The present invention relates generally to grounding switches for a compressed-gas-insulated, metal-encased high-voltage switching systems, and more particularly to such a grounding switch in which the casing as well as the housing is applied to ground potential. Furthermore, the present invention relates to such a grounding switch in which the movable switching piece is insulated in gas form or by insulation material in the housing of the grounding switch, and is moved by a rotating drive shaft. Finally, the present invention relates to such a grounding switch in which the drive shaft passes through the housing, and contact elements transfer the ground potential to the movable switching piece, where the connection to the ground potential is disconnectable.
EP-A-0 075 922 discloses such a grounding switch. This known grounding switch serves not only to transfer the ground potential, but is also insulated for measurement purposes. For this reason the disconnectable connection to ground potential, which is structured so as to be disconnected, is eliminated. In the known grounding switch, a ring of insulation material is provided between the casing of the high-tension switching system and the housing of the grounding switch, which galvanically separates the two parts. These two parts normally carry ground potential. The means for transferring ground potential to the movable switching piece has slide contacts resting against the switching piece and is insulated relative to the housing of the grounding switch, thus making the switching piece suitable also to carry measurement currents.
The present invention is directed to the problem of developing a means for transferring ground potential to the movable switching piece in the above described grounding switch, in a particularly simple manner.